Field of the Invention and Related Art Statement
The present invention relates to R-enantiomers of .DELTA..sup.2 -1,2,4-triazolin-5-one derivatives represented by general formula (I): ##STR2## wherein R.sup.1 represents a fluoroalkyl group having 1 to 2 carbon atoms and R.sup.2 represents a hydrogen atom, a chloroalkyl group having 1 to 4 carbon atoms or an alkoxyalkoxyalkyl group having the total carbon atom numbers of 3 to 6, and herbicidal compositions comprising these derivatives as active components.
A part of the racemic modification of compounds represented by general formula (I) is known in Japanese Patent Application KOKAI (Laid-Open) Nos. 255780/85 and 205265/86 but optical isomers thereof are novel compounds which are not found in publications.
As the prior art of the present invention, compounds similar to those of the present invention are disclosed in U.S. Pat. Nos. 4,318,731, 4,404,019, 4,398,943, 4,427,438 and 4,452,981, Japanese Patent Application KOKAI (Laid-Open) Nos. 181069/82, 255780/85 and 205265/86, PCT Disclosure Nos. W085/01637, W085/04307, W086/00072, W086/02642 and W086/04481, etc. However, nothing is suggested or specifically disclosed with respect to optical isomers of the present invention. In addition, R-enantiomers of the .DELTA..sup.2 -1,2,4-triazolin-5-one derivatives in accordance with the present invention exhibit a remarkable herbicidal effect which is unexpectedly superior to the known racemic compounds.